1. Field of the Invention
The invention relates to an automatic latch means for a hopper car door actuator, and more particularly to such a latch means which will automatically lock to the hopper car frame the door actuator in its closed position under all dynamic conditions of the hopper car, until purposefully released.
2. Description of the Prior Art
Heretofor the discharge doors of a hopper car have generally been opened and closed manually, each door being provided with its own manually actuated latch means by which it may be locked in its closed position. More recently, hopper cars have been made of greater size and capacity with larger and heavier hopper doors. Prior art workers have devised for such cars various types of automatic door actuating means by which the hopper doors may be mechanically opened and closed. At the same time, various types of latch means have been developed to lock the door actuating means in its door-closing position, thereby maintaining the hopper doors in their closed position. Examples of such latch means are taught in U.S. Pat. Nos. 2,893,327; 3,166,024; 3,710,729 and 3,772,996.
Prior art door actuator latch means have frequently been characterized by complex structure and have been difficult and expensive to manufacture and assemble. Furthermore, many of the prior art latch means were of such nature that under certain dynamic conditions of the hopper car (including humping, train shocks, train action and slack run-in and run-out) the latch means would unintentionally assume an unlatched condition with the possible risk of unwanted discharge of the car load.
The present invention provides an automatic latch means for a hopper car door actuator of the type comprising a link or beam shiftable longitudinally by a fluid cylinder between door opening and door closing positions. The automatic latch means of the present invention is intended to overcome the deficiencies enumerated above, being characterized by simplicity of construction and ease of manufacture and installation. The latch means is positive in its action under all dynamic conditions of the hopper car and is provided with means to prevent inadvertent unlatching when impact inertia tends to extend the piston rod of the fluid cylinder.